The present invention generally relates to devices for lifting and towing vehicles by a pair of the vehicle wheels, known as wheel lifts. More particularly, the invention is directed to a self-loading wheel lift that may be rapidly disassembled for transportation or repair and/or rapidly converted or transformed for other applications.
Commonly assigned U.S. Pat. Nos. 4,637,623 and 4,798,509 to Alm, each entitled “Towing Apparatus,” and U.S. Pat. No. 4,836,737 to Holmes entitled “Wheel Lift Tow Assembly,” each disclosing known wheel lift assemblies, as well as U.S. Pat. No. 4,564,207 to Russ et al., entitled “Hydraulic Wheel Lift System For Tow Vehicles,” are each hereby incorporated by reference in their entirety into this application.
For years the standard hydraulic self-loading wheel lift, such as depicted in U.S. Pat. No. 4,564,207 to Russ et al. has enjoyed a specific usage in the towing industry. While capable of automatically loading automobiles in seconds with ease and permitting operators to remain in the safe environment of their cab, self-loading wheel lifts can only load those automobiles possessing tires. Such wheel lifts are also limited by their inability to handle the weight of larger trucks and the like. The typical assembly of such wheel lifts includes a cross bar roughly 80 inches long for capturing the towed vehicle's tires. Two wheel support members such as L-shaped arms may be pivotally attached to the cross bar, swinging from inside and then outwardly to capture a towed vehicle's tires. Hydraulic cylinders, for example, may power L-arm movement. In the past, the wheel support members of self-loading wheel lifts have not been designed to be removed from the cross bar.
Conventional wheel lifts are also an industry standard and have been in the towing industry for years. These wheel lifts, exemplified by those disclosed in U.S. Pat. Nos. 4,637,623, 4,798,509 and 4,836,737, are more versatile than self-loading wheel lifts in some ways, as they are capable of loading vehicles with or without tires, as well as heavier vehicles such as heavy trucks. However, the process required to engage a towed vehicle using a conventional wheel lift is considerably longer than with a self-loading wheel lift, and may take ten minutes or longer. In addition, the tow truck operator must exit the cab to manually place the L-arms or other tow-engaging attachments, exposing him to the elements and traffic. The typical assembly of a conventional wheel lift includes a cross bar roughly 40-60 inches in length. Two shoes are slid over opposing ends of the cross bar, and pivoting collars may be mounted to the shoes. The collars engage L-arms that are manually placed to engage the tires or other locations on a towed vehicle. The L-arms are designed to engage points on the towed vehicle from the outside in, limiting their ability to engage tires located adjacent curbs, for example. While some conventional wheel lifts may be converted from using L-arms to a tool bar, the conversion has been manual and time-consuming, and the L-arms were unable to swing from the inside out, limiting their application.
Self-loading or conventional wheel lift assemblies have not been previously designed, to applicant's knowledge, to permit rapid disassembly in the field or to allow rapid conversion to an alternate towing mechanism. Often, the cross bar of wheel lift-type tow mechanisms includes shoes or brackets that are welded to the ends of the cross bars. Additionally, the presence of permanently attached powering mechanisms such as hydraulic cylinders may render it difficult and time-consuming to remove wheel support members and/or receivers from the cross bar. In short, it is not believed that self-loading wheel lifts have been designed with the ability to rapidly convert or transform the wheel lift device into an alternate towing mechanism, such as a tool bar or frame fork attachment.
Accordingly, it would be advantageous to provide a self-loading wheel lift that overcomes the current disadvantages of such wheel lifts, while providing new advantages.